Liquid detergent compositions

ABSTRACT

THE INVENTION RELATES TO NOVEL LIQUID DETERGENT COMPOSITIONS CONSISTING ESSENTIALLY OF N(2-HYDROXY C10-C18 ALKYL) DERIVATIVES OF N-METHYL TAURINE OR SARCOSINE OR DIETHANOLAMINE IN COMBINATION WITH ON ANIONIC SULFATE, ZWITTERIONIC, OR AMPHOTERIC DETERGENT IN AN AQUEOUS MEDIUM. THE ADDITION OF THE N(2-HYDROXY C10-C18 ALKYL) DERIVATIVES RESULTS IN SUBSTANTIALLY INCREASED FOAM-DRAINAGE TIMES AND BETTER FOAMING PROPERTIES.

United States Patent 3,723,357 LIQUID DETERGENT COMPOSITION Kenneth R. Hansen, Staten Island, N.Y., assignor to Colgate-Palmolive Company, New York, N .Y. No Drawing. Filed Nov. 16, 1970, Ser. No. 90,152 Int. Cl. Clld l/84 US. Cl. 252-545 5 Claims ABSTRACT OF THE DISCLOSURE The invention relates to novel liquid detergent compositions consisting essentially of N(2-hydroxy C -C alkyl) derivatives of N-methyl taurine or sarcosine or diethanolamine in combination with on anionic sulfate, zwitterionic, or amphoteric detergent in an aqueous medium. The addition of the N(2-hydroxy C C alkyl) derivatives results in substantially increased foam-drainage times and better foaming properties.

This invention relates to liquid detergent compositions consisting essentially of a water-soluble, foaming detergent selected from the group consisting of anionic sulfate, amphoteric, and zwitterionic detergents and mixtures thereof in combination with an N-(Z-hydroxy-higher alkyl) derivative of an N-methyl taurinate, sarcosinate, or diethanolamine in an aqueous medium. Such liquid detergents are characterized by a rich, slow-draining foam which provides ample liquid within the foam to remove surface oil and dirt.

An important consideration in the formulation of liquid detergents suitable for use in hand washing, shampooing, or dishwashing is their ability to form a large quantity of foam or lather which is stable in the presence of greasy soils and dirt. It is desirable that such products should yield a copious, stable foam or lather in both hard and soft water. The most desirable foam is one which is slow draining and persistent.

The properties of foam are influenced by a variety of factors, such as the extent of adsorption from solution at liquid-gas interfaces, gaseous diffusion, bubble-size distribution, and temperature. Ultimately, foam properties are primarily dependent upon the chemical composition and characteristics of the adsorbed film. The composition of the solution from which foam is made and the extent of drainage and breakdown will influence the shape and size distribution of the bubbles.

The drainage rate is retarded with an increase in bulk and surface viscosity and with a decrease in bubble size, and it is believed that slow-draining films are due to an ordered surface structure with a rigid film and high surface viscosity. Slow-draining foams also remain wetter than fast-draining foams and have higher consistencies.

It has been discovered that certain N (2-hydroxy C C alkyl) derivatives of N-methyl taurine, sarcosine, and diethanolamine detergents (hereinafter referred to as drainage-time extenders) change the drainage characteristics of foam generated by anionic sulfate, zwitterionic, and ampholytic or amphoteric detergents from fast draining to slow draining and also improve the total amount of foam generated in many cases.

Patented Mar. 27, 1973 In general, the liquid detergent compositions of this invention consist essentially of (I) about 5 percent to 35 percent of water-soluble, foaming detergent selected from the group consisting of anionic sulfate, zwitterionic, and amphoteric detergents, and mixtures thereof; (II) 2 percent to 27 percent of a drainage-time extender selected from the group consisting of N-(Z-hydroxy C -C alkyl) derivatives of N-methyl taurinate, sarcosinate, N-methyl taurinate-N-oxide, sarcosinate N oxide and diethanolamine; the sum of (I) and (II) being about 10 percent to 40 percent by weight of the composition; the ratio of detergent to drainage time extender being from the range of 20:1 to 1:20 and sufficient to improve the foam stability; and (III) an aqueous medium.

The water-soluble drainage-time extenders which are suitable for use in the compositions of the invention have the-following formula wherein R is an alkyl group having from 8 to 16 carbons and Y is selected from the group consisting of N(CHa) CHzCHzSOaM, N(CHZ) CHzCOzM and N(CH CH OH) wherein M is selected from the group consisting of sodium, potassium, ammonium and mono, di, and triethanolammonium.

The N-(Z-hydroxy higher alkyl) N-methyl taurinates have the formula RCH (OH) CH N (CH CH CH SO M and may be prepared by simple addition of N-methyl taurine salt to a 1,2 epoxyalkane containing about 10 to 18 carbon atoms. The addition technique produces the desired N-(Z-hydroxyalkyl) N-methyltaurine salt which is relatively free from inorganic impurities. The epoxide raw material is made by conventional oxidation of compounds derived from petroleum.

The N-oxide derivatives of the N-(2 hydroxyalkyDN- methyl taurinates may be prepared by oxidizing the corresponding N(2 hydroxyalkyl)N-methyl taurinate with hydrogen peroxide or ozone to convert the amine to an amine oxide.

The N(2 hydroxyalkyl) diethanolamine has the formula R-OH(OH)CH N(C H OH) and may be prepared in the same fashion as the taurinates above by addition of diethanolamine to an alcoholic solution of the desired 1,2 epoxyalkane at a neutral or alkaline pH.

The N(2 hydroxyalkyl) sarcosinates have the formula RCH(OH)CH NCH CH CO M and may be prepared, for example, in the following manner.

An equimolar mixture of a long-chain 1,2-epoxide and a 32 percent aqueous solution of sodium sarcosinate is heated to 110 C. with vigorous stirring. After a period of time (10 to 30 minutes, depending on the chain length of the epoxide) an exothermic reaction takes place. As the reaction mixture becomes viscous, crushed ice is added to lower the temperature to between and 98 C. The

reaction mixture is held at this temperature for 30 minutes, adding crushed ice as necessary to control the temperature. The Water in the reaction mixture is removed by freeze drying. The reaction mixture is slurried in boiling acetone to extract the unreacted epoxide and then recrystallized from ethanol or isopropanol. The reaction mixture is then dissolved in isopropanol, and any water azeotroped off. The product crystallizes from the alcohol upon cooling. The reaction mixture is cooled to about 70 C. and methyl ethyl ketone (2 to 3 times the volume of the reaction mixture) is added. The product upon stirring and cooling solidifies as a suspension in the ketone. The products if filtered off, dried and recrystallized from ethanol or isopropanol.

The general equation for the reaction of alkane-1,2- epoxide with sodium sarcosinate is:

The N-oxide of sodium N(2 hydroxy alkyl) sarcosinate can be prepared, for example, in the following manner. One hundred thirty-two pounds of sodium N(2 hydroxy alkyl) sarcosinate is charged into the glass-lined reactor, and cooling water is applied on the jacket. Twenty-one pounds of 3S-percent hydrogen peroxide is slowly added. An exothermic reaction takes place between 120 and 140 F. and the product obtained has the appearance of a light foam, which later settles to a yellow solution. When the reaction is over, the excess peroxide is destroyed, for example, as by adding sodium sulfite.

The general equation for the reaction of sodium N(2 hydroxy alkyl) sarcosinate with hydrogen peroxide is:

(DH (EH3 OH (IJH RCHCHQNCH2COON3. H2O; RHCHzIIICHzCOONa 1120 The preferred foam-drainage extenders are sodium N(2 hydroxy hexadecyl) methyl taurinate, sodium N (2-hydroxy hexadecyl) sarcosinate and sodium N(2-hydroxy hexadecyl) sarcosinate N-oxide.

The foam-drainage extenders are generally present in an amount of from about 2 to 27 percent, preferably 3 percent to 20% by weight.

The water-soluble foaming detergents which are suitable for use in the compositions of the invention are selected from the group consisting of higher alkyl sulfates, higher alkyl ethenoxy ether sulfates, higher alkyl betaines, higher alkyl sulfobetaines, higher alkyl aminopropionates, higher alkyl iminodipropionates, higher alkyl imidazolines, and mixtures thereof, wherein the higher alkyl group contains from to 16 carbon atoms. Generally, these detergents are present in the form of a salt wherein the water soluble cation is selected from the group consisting of sodium, potassium, ammonium, and mono, di, or triethanolammonium salts.

The anionic sulfate detergents which may be used in the shampoo compositions of this invention have the structural formula R(OC H OSO M wherein R is a C to C alkyl group, In is 0 to 5, and M is one of the watersoluble cations mentioned in the foregoing paragraph. Examples of the anionic sulfates are sodium and triethanolamine lauryl sulfate and sodium lauryl triethanoxy ether sulfate.

The sodium and alkylammonium salts are the most highly preferred anionic sulfate detergents.

Zwitterionic detergents, such as the betaines and sulfobetaines, are also useful as the foaming detergent in the composition of the invention. Suitable betaine detergents have the formula Z(N)R R CH CO wherein Z is an alkyl radical selected from the group consisting of C -C alkyl, C -C alkyl amidoethyl, and C C alkyl amidopropyl and R and R are C -C alkyl or C C hydroxyalkyl. The alkyl dimethyl betaine and the alkyl amidopropyl dimethyl betaine detergents are the preferred zwitterionic detergents.

The N-alkyl sulfobetaines having the formula RNR R (C-H ),,SO

wherein R is C -C alkyl, R and R are C -C alkyl or C -C hydroxyalkyl and n is 1, 2 or 3 are also satisfactory zwitterionic detergents.

The amphoteric detergents which can be used in the compositions of this invention are generally water-soluble salts of derivatives of aliphatic amines which contain at least one cationic group, e.g., non-quaternary nitrogen or quaternary ammonium group, at least one alkyl group of about 10 to 16 carbon atoms and an anionic watersolubilizing carboxyl, sulfo or sulfato group in their molecular structure. The alkyl group may be straight chain or branched and the specific cationic atom may be part of a heterocyclic ring.

Examples of suitable ampholytic detergents include the higher alkyl beta-aminopropionates, RN(H)C H COOM; the higher alkyl beta-iminodipropionates,

RN (C H COOM 2 and the long-chain imidazole derivatives having the following formula:

N CH2 W 1" RzCOOM wherein R is an alkyl group of about 10 to 16 carbon atoms, W is selected from the group of R OH, R COOM, and R OR COOM, Y is selected from the group consisting of OH, 11 050 R is an alkylene or hydroxyalkylene group containing 1 to 4 carbon atoms, R, is selected from the group consisting of alkyl, alkylaryl and fatty acyl glyceride groups having 6 to 18 carbon atoms in the alkyl or an acyl group; and M is a water-soluble cation, e.g., sodium, potassium, ammonium or alkylolammonium.

The alkyl beta-aminopropionates and iminodipropionate detergents are well known as are the imidazoline detergents which are described in US. 2,773,068; US. 2,781,354, and U8. 2,781,357. The alkyl groups may be derived from coconut oil fatty acids (a mixture of fatty acids containing 8 to 18 carbon atoms), lauric fatty acid, and oleic fatty acid and the preferred groups are C -C alkyl groups. A preferred amphoteric detergent is sodium N-lauryl beta-aminopropionate.

Generally, the foaming detergent will be present in an amount of 5 percent to 35 percent by weight of the liquid detergent composition. Preferably, the proportion of foaming detergent will be about 10 percent to 30 percent by weight. Further, the sum of the foaming detergent and the drainage-time extender should be about 10 percent to 40 percent, preferably 15 percent to 30 percent, by weight of the final liquid detergent.

The ratio of foaming detergent to drainage-time extender is variable and depends upon the particular detergent and the particular drainage-time extender. Generally, the detergent-to-drainage-time-extender ratio is selected from the range of about 20:1 to 1:20, preferably about 9:1 to 1:9 by weight, most preferably from about 9:1 to 1:1 by weight, said ratio being effective to improve the foam stabilit of the detergent. Since optimum foam stability and optimum foam volume do not usually occur at the same detergent-to-drainage-time-extender ratio, the particular ratio selected usually represents a compromise which is elfective to provide both enhanced foam stability and enhanced foam volume.

The aqueous vehicle or medium comprises the balance of the composition. Generally, the aqueous medium is water or a mixture of water and a C -C monohydric or polyhydric alcohol, such as ethanol, isopropanol, or propylene glycol. Since the C -C alcohol is an optional ingredient, its proportion is variable and amounts generally to 1 percent to percent of the liquid detergent composition. A preferred alcohol concentration is from about 2 percent to about 8 percent by weight of the composition. Where clear liquid compositions are desired, the amount of the aqueous medium, and the composition thereof should be effective to dissolve or to solubilize the active ingredients. Preferred aqueous media are water and mixtures of water and ethanol.

Generally, the pH of the liquid detergent compositions is in the range of 5.5 to 10.0 with the pH range of 6.5 to 9.0 being preferred. The pH is adjusted, where necessary, in the conventional manner by adding acids, such as sulfuric, hydrochloric and citric acid, or by adding bases, such as sodium hydroxide, potassium hydroxide or triethanolamine.

A coupling agent, such as the lower alkyl benzene sulfonates, may also be included in the liquid detergent compositions of this invention to lower their cloud points at elevated pH ranges. The preferred compound is sodium hexyl benzene sulfonate. Such coupling agents usually are present in an amount of from about 0.3 to 4 percent, preferably about 0.5 to 2 percent.

Additional ingredients may be incorporated into the liquid detergents. Such ingredients include compatible thickeners, lanolin, coloring agents, perfumes, sequestering agentssuch as tetrasodium diaminotetraacetate-and opacifiers, such as zinc stearate, polyethylene glycol 600 monostearate or ethylene glycol monostearate and magnesium stearate, which are useful in enhancing the aesthetic and cosmetic properties of liquid formulations. These ingredients are incorporated in conventional amounts varying from about 0.1 percent to about 4 percent.

From the viewpoint of foaming, the compositions of this invention are characterized by increased foam-drainage times or increased foam stability produced during shampooing operations as compared with the foaming effects obtained for compositions without the drainagetime extender. The foam of the compositions containing the drainage-time extender has good creaminess and consistency, has a long drainage time, and contains an increased amount of liquid. The inventive compositions also exhibit a greater capacity for holding in suspension larger amounts of grease or hair soil with less foam loss.

To evaluate the foaming characteristics of the compositions, 25 grams of detergent solution or shampoo solution are diluted to 100 milliliters with water containing 250 parts per million of hardness (160 ppm. of Ca++ and 90 ppm. of Mg++) in the presence of three grams of synthetic sebum soil, and the temperature of the mixture is adjusted to 100 F. The one hundred milliliters of solution is then transferred to a five hundred milliliter graduated cylinder containing a water-filled plastic cylinder (17 millimeter diameter, 72 millimeter height, and a displacement volume equal to twenty-five milliliters of water), and the 500 milliliter cylinder is aflixed to a mechanical rotator assembly Where it is rotated through twenty complete cycles or revolutions to generate foam. Rotations are completed within thirty-five to fifty-five seconds. The foam volume is noted at the conclusion of the rotations, and the time interval in seconds from the completion of the rotations to the point at which seventyfive millimeters of liquid have been drained is recorded as the drainage time.

The concentration of detergent in the detergent solution in the foregoing test is variable and generally ranges from ten percent to thirty percent by weight as such concentrations are typical of the commercial dishwashing and shampoo products.

The composition of the synthetic sebum soil used in the test procedure is ten percent palmitic acid, five percent stearic acid, fifteen percent spermaceti, twenty percent olive oil, five percent squalene, five percent chlosterol, ten percent oleic acid, and five percent linoleic acid all percentages being by weight.

Table I sets forth comparative results for foam-drainage time or foam endurance for six compositions using the aforementioned procedure. Composition A consists of thirty percent by weight of triethanolamine alkyl sulfate in Water. The alkyl group distribution of the alkyl sulfate is about 65% C 27% C and about 8% C Composition B consists of thirty percent by weight of sodium, N(2 hydroxy hexadecyl)N-methyl taurinate in water, and Compositions C, D, E, and F contain thirty percent by Weight of a mixture of triethanolamine alkyl sulfate (TEAAS) and sodium N-(Z-hydroxy hexadecyl) N-methyl taurinate (NaHHT) in the stated proportions in water. For purposes of comparison, the drainage time may be expressed as a percentage of the calculated drainage time based upon the drainage times for the individual detergents at the thirty percent concentration. The Observed drainage time in. seconds for Composition A containing thirty percent by weight TEAAS equals one hundred percent, and the observed drainage time for the drainage-time extender is expressed as a percentage of the time for Composition A.

All of the compositions in Table I exhibit a higher foam volume at the conclusion of the rotations than would be expected from the foam volume of 30% concentrations of the individual detergents.

When sodium lauryl sulfate or sodium lauryl triethenoxy ether sulfate is substituted for triethanolamine alkyl sulfate in the compositions of Table I containing the sodium N-(2 hydroxyl hexadecyl) N-methyl taurinate and evaluated using the described procedure similar enhanced drainage values are obtained. The lauryl group in the substituted detergents is obtained from the fatty acid mixture found in coconut oil, and the alkyl distribution therein is 1.0 percent C 6069 percent C 2429 per cent C 5-10 percent C and 0.5 percent C Similar enhanced foaming results may be obtained when the potassium, ammonium, monoethanolammonium, and diethanolammonium C -C alkyl sulfate salts are used in place of the sodium or triethanolammonium alkyl sulfates.

Table I indicates that enhanced foam drainage values are obtained at weight ratios of foaming detergent to sodium N-(Z hydroxy hexadecyl) N-methyl taurinate drainage-time extender in the range of about 9:1 to 1:9. Optimum foam-drainage times are generally noted at foaming detergent to sodium N-(Z hydroxy hexadecyl) N- methyl taurinate drainage-time extender ratios in the range of 9:1 to 111.

Table II indicates the results obtained in similar tests in which the concentration of the aqueous detergent compositions is twenty percent by weight of active ingredient.

TABLE 11 Percent relative foam Composition: drainage value 20% TEAAS 20% NaI-ll-IT 32 15% TEAAS5% NaHHT (3:1) 440 The unusual effects noted for the compositions set forth in Tables I and II are self-evident. Clearly, the compositions of the invention exhibit enhanced foam stability in comparison to the effects expected from the stability of the individual detergent under the same test conditions.

Table III sets forth comparative foam-drainage values for compositions containing triethanolamine alkyl sulfate in combination with other foam-drainage-time-extender ingredients.

TABLE III Percent relative foam Composition: drainage value 30% TEAAS 100 30% NaHHS 1 153 24% TEAAS-6% NaHHS (4:1) 370 6% TEAAS-24% NaHI-IS (1:4) 370 30% NaHHSO 2 450 27% TEAAS-3% NaHHSO (9:1) 340 21% TEAAS9% NaHHSO (7:3) 640 6% TEAAS-24% NaHHSO (1:4) 600 30% HHDEA O 15% TEAAS15% HHDEA (1:1) 1000 27% TEAAS3% HHDEA (9:1) 440 12% TEAAS-18% HHDEA (1:1.5)

Sodium N(2-hydroxy hexadecyl) sarcosinate. Sodium N-(2-hydroxy hexadecyl) sarcosinateN-oxide. 3 N-(2 hydroxy hexadecyl) diethanolamine.

The results in Table III demonstrate that the N(2-hydroxyalkyl) sarcosinates and their N-oxide derivatives are similar to the N(Z-hydroxyalkyl) N-methyl taurinates as drainage-time extenders and are effective at foaming detergent to drainage-time extender ratios of 9:1 to 1:9. Also, like the taurinate foam extenders these materials provide enhanced volumes of foam over the same range as compared with calculated foam volume based upon the foam volume of the individual materials at the thirty percent concentration. However, the N-(Z-hydroxylalkyl) sarcosinate foam extender and its N-oxide derivative differ from the N-(2-hydroxyalkyl) N-methyl taurinate material in that these materials individually exhibit greater foam-drainage values than the foaming detergent.

Table III also indicates that the N(Z-hydroxyalkyl) diother drainage-time extenders because it individually does not have any foam stability and its use as a drainagetime extender is limited to foaming detergent drainagetime extender ratios in the range of 9:1 to 1: 1. Similarly to the other drainage-time extenders, the total foam volume is enhanced in the 9:1 to 1:1 ratio range as compared with the calculated effect based upon the foam volumes of thirty percent aqueous concentration of each individual component.

Enhanced foam-drainage times are obtained when sodium N-(Z-hydroxyhexadecyl) N-methyl taurinate is used in combination with either sodium C C alkyloamidopropyl dimethyl betaine detergent or C -C alkyl dimethyl sulfobetaine detergent. As with the alkyl sulfate detergents, enhanced foam stability and enhanced foam volume are exhibited at detergent to drainage-time extender ratios in the range of 9:1 to 1:9. Sodium N(2-hydroxyhexadecyl) N-methyl taurinate also improves the foam stability and foam volume of sodium N-laurylmyristyl beta aminopropionate, with optimum stability values being obtained in the range of about 1.5:1 to 1:1.5.

For optimum foam stability, the best ratios of sodium N(2-hydroxyhexadecyl) N-methyl taurinate to various foaming detergents is as follows:

1 taurinate to 9 sodium lauryl sulfate 1 taurinate to 1.5 triethanolamine lauryl sulfate 1 taurinate to 1.5 sodium lauryl ether sulfate 1 taurinate to 2.3 C -C alkyl amidopropyl dimethyl betaine 1 taurinate to 1 N-lauryl myristyl beta amino propionate 1 taurinate to 2.3 C -C ammonium alkyl sulfobetaine The preferred ratio of Z-hydroxy hexadecyl diethanolamine to triethanolamine lauryl sulfate is about 1 to 4 optimum. For the 2 hydroxyhexadecyl sarcosinate N- oxide, the preferred ratio to triethanolamine lauryl sulfate is 1 to 1.5 for optimum foam drainage time.

Additional shampoo compositions which exemplify the described invention are disclosed in Examples 1 and 2 which follow. Each of these compositions exhibits high taine 22.5

Sodium N(Z-hydroxyhexadecyl) N-methyl taurinate 6.0 Water Balance The foregoing composition is a clear liquid having a cloud point below 30 F. and exhibits high foam stability and high foam volume in the presence of sebum soil in the described testing procedure. Its pH is 8.7.

EXAMPLE 2 Percent Sodium lauryl sulfate 27.0 Sodium N(2-hydroxyhexadecyl) N-methyl taurinate 3.0 Sodium hexylbenzene sulfonate 1.0 Water Balance This composition exhibits a high foam volume and high foam stability. It is also a clear liquid having a cloud point at about 54 F. and a pH of 9.6. Its foam volume is greater than that of the composition of Example 1, but its foam stability is less.

The mixture of detergent and foam drainage time extender should be free from inorganic salts in an amount which adversely affect the foaming power or effect. For example, the presence of phosphate builder in an amount equivalent to the detergents substantially inhibits attainment of the desired improvement in foam stability.

Although the present invention has been described with reference to particular embodiments and examples, it will be apparent to those skilled in the art that variations and modifications of this invention can be made and that equivalents can be substituted therefor without departing from the principles and spirit of the invention.

What is claimed is:

1. A liquid detergent composition having enhanced foam stability which consists essentially of (I) 5% to 35% by weight of a water-soluble foaming zwitterionic detergent selected from the group consisting of N-alkyl sulfobetaines having the formula and alkyl betaine detergents having the formula Z(N) R R CH CO wherein R is an alkyl group of 10 to 16 carbon atoms, R and R are C C alkyl or C -C hydroxyalkyl, n is 1-3, Z is selected from the group consisting of R, RC(O)NC H or RC(O)NC H (II) 2% to 27% by weight of a watersoluble drainage-time extender having the formula wherein R is an alkyl group containing 14 carbons and M is selected from the group consisting of sodium, potassium, ammonium and mono, di, and triethanolammonium, the sum of (I) and (II) being 10 percent to 40 percent by weight of the composition; the weight ratio of said detergent to drainage time extender being from the range of 9:1 to 1:1 and sufficient to improve foam stability; and (III) an aqueous vehicle selected from the group consisting of water and a mixture of water and a C -C monohydric or polyhydric alcohol.

2. A composition as set forth in claim 1 wherein said drainage time extender is the sodium salt.

3. A composition as set forth in claim 1 wherein said foaming detergent is an alkyl amidopropyl dimethyl betaine.

4. A composition as set forth in claim 1 wherein said foaming detergent is an alkyl dimethyl sulfobetaine.

5. A composition as set forth in claim 2 wherein the sum of the foaming detergent and drainage-time extender concentrations is from 15 percent to 30 percent by weight.

References Cited UNITED STATES PATENTS 2,979,465 4/1961 Parran et a1 252--137 3,085,067 4/ 1963 Anderson 252152 X 3,317,430 5/ 1967 Priestley et a1 252-152 OTHER REFERENCES Pitts: Amino-Sulfonates, pp. 20-22, 70.

LEON D. ROSDOL, Primary Examiner 10 H. A. PITLICK, Assistant Examiner U.S. Cl. X.R.

252546, 548, DIG 713 

